Improvement in extension-bit



To all whom it may concern.-

tite.

E.l P. CHAPMAN, or EssEx, AssIeNoE To 'PHE CENTRE EEooK MANU- EACTUEINGCoMPANY, CE CENTRE EEooK, CONNECTICUT.

Letters :Patent No. 97,166, dated November 23, 1869.

IMPROVEMENT IN EXTENSION-BIT.

The Schedule referred to in 'these Letters Patent and making partA ofthe same.

Be it known 'that I, H. P. CHAPMAN, of Essex, in the county ofMiddlesex, ztndvStzlte ot Connecticut, have invented :t newIn'iploveluent h1 Extensionfits; and I do hereby declare the following,when taken in connection with the :tcconipzuiying drawings, amd theletters of' reference marked thereon, to be :L full, cleur, :md exactdescription ofthe seme, and which said dmwngs constitute purt of thisspecification, zuid'represent, in

l Figure 1, n front View;

Eigui'ie 2. a. sideview, and in Figure 3, :tperspective view, in whichthe fixedcutter is constructed to throw the chips buck.

This invention relates to u improvement in exten.-

sion-bits, that is to say, bits constructed with an ad-v justztblecutter, so as to bore holes ot' different sizes; and 1 The inventionconsists in constructing the adjustable cutter with zt slot, the twoedges ot' which are inclined, und so as to receive :L conical-headedset-screw, theconicul head of the screw tending to open the slot, so asto fix the cutter in its sent; also, in constructing the fixed cutter ofu gouge shape, and so as to throw the chips Veither to the front or rearof the adjustable cutter. g

lo enable others skilled in the zn't to make und use my invention, lwillproceed to describe the seine, as illustrated in the accompanyingdrawings.

A is the shankhor spindle ot' kthe bit, constructed with :t heztd, B,the lower end. of which is rounded, or sphericnl slmpe, and. in the saidrounded en d .zt.lip, a., is formed, which serves as the cutter, mldmakes what we term n gouge-lip, the whole terinimttingr in a. pointedscrew, d.

G is the adjustable cutter', constructed with n slot,

f, opening 'from oneside, und, by preference, nem-erA the upper thanlower edge, :is seen in fig. 1.

'Upon the lower edge, the cutting-lip h-islforrned, as also a spur, t,the cutter and spur being of common construction.

The siot f is inclined upon itsedges, asseen in figs. 1 und 2, and s oes to receive the conical head of the 13, 1868, and NV. A. Clark, Malywww set-screw D, which is turned into the head B of the bit, so as todraw down into the slot, and press the cutter C to its seat.

The cutter, being placed in :t groove or slot formed inthe face of thehea-d, the Ytendency ot' the conical screw-heed is to open the slot j,and thus wedge the cutter between the upper and lower edge ot' thegroove or slot in the heztd ofthe bit.` By this means, the cntter isheld in the firmest manner, and the construct-ion is extremely simple.

It' preferred, and in large bits it may be advisable,

theupper and lower edge of the groove or slot in the.A

structed accordingly, and thus nid in the holding ot" the cutter; butsuch construction is not essential, I'ind, in practice, the slot j,'with theconicnl screw, to be all suflicient. v

The lip afmzty be constructed on either side, that is to stty, as in g.2 or iig. 3, so es to throw the Chips eitherto the front or rear.

I nm aware of the patents of W. A. Ives, October l1, 1858, reissued June22, 1868, and do not wish to be lunderstood as claiming anything foundin the two patents.

Having fully described my invention,

Whnt I claim ns new :nid useful, und desire to se cure by LettersPatent, isf 1. Thehead or fixed cutter, constructed so as to form :tgouge-lip or cutter, a, in combination with a cutter, U, mede adjustablein the head above said gouge-lip a, substantially es set forth.

2. 1n adjustable bits, the cutter C, when constructed v with the slot f,with its inclined edges, and combined with the conical-heededset-screwD, so that the said screw will spread each side from the slot,to bind the cutter into its seat, substantially in the manner andA forthe purpose set forth. f

.H. P. CHAPMAN.

Witnesses:

, J. H.YSHUMWAY, A. J. TU BI'rs.

